Control Time

Frame interval timer

A frame interval timer like this can be had for around $30 on eBay

Being a big Dr. Who fan, I’m fascinated with the idea of manipulating time.  With time lapse photography you can play Time Lord and compress hours worth of activity into just a few seconds.  Today we’ll cover how that process works.

What you’ll need:

- A camera that has an interval timer or that accepts a third party timer.

- A big storage card or the ability to change cards in the middle of shooting

- A tripod

- A really good battery or plug-in power

- A video editing system with the ability to import a series of images as video

The Formula

I use 24 frames per second as my standard because it fits with my video time lines, which are either 24 or 30 fps.  The math works like this for 24p:

Length of event:  2 hours
Desired length of final video segment:  60 seconds
Number of frames needed for final video segment:  60 x 24 = 1,440

2 hours is 7,200 seconds.

To compress 7,200 seconds into 1,440 frames that means 1 frame every 5 seconds (7200/1440).

That means each actual minute of real time will be 0.5 seconds of video.  The Doctor would be proud of you.  One frame every five seconds should yield a nice, smooth compression, provided there isn’t a lot of detail.  That would be perfect for clouds, sunrises and smooth continuous motion.  If the shot has a lot of moving parts, like people and cars moving around, you may want to raise the frame rate for more continuity in the final product.  Otherwise you have cars suddenly appearing and disappearing in the video instead of driving through.

Storage

In the example above my Canon 7D can fit approximately a 1,000 pictures (small jpg setting) on an 8 Gig storage card.  To shoot the sequence above, I would either need to switch cards in the middle of the shoot…tricky, but I’ve done it.  Or get a bigger card.  The larger the storage card the more frames it will hold.
That’s why doing the math is not optional.  If you need to change the battery or storage card in the middle of your time lapse, you need to be prepared in advance.  Hey, don’t complain, your 5th grade math teacher warned you this day would come.

Process

Set up your tripod and mount your camera.  I use auto-exposure in case cloud cover moves in or lighting changes, not everyone agrees with that setup decision but it’s convenient.

I leave my camera set on auto-number, in sequence.  If you don’t have that enabled on your camera, set it up before you start your time lapse.

Set the camera or external interval timer.  The timer I have can only go up 399 pictures, so I have to be there periodically to hit the reset button.

Let the camera run, upload your pictures to a folder and import the sequence into your video editor.

Here’s an example of one I shot some time ago.  Weather Time Lapse



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